I recently purchased a Kershaw Packrat and a Kershaw Blur. I'm liking the Blur, no problems with it at all. But my Kershaw Packrat 1665CST I'm having trouble deploying the blade. I don't see any safety on it or in any review videos. Yet I'm pulling on the blade, pushing on the flipper and I can't get it to even move a little bit. Does anybody know what could be keeping it shut?